2,324 research outputs found
Absence of continuous spectral types for certain nonstationary random models
We consider continuum random Schr\"odinger operators of the type with a deterministic background potential .
We establish criteria for the absence of continuous and absolutely continuous
spectrum, respectively, outside the spectrum of . The models we
treat include random surface potentials as well as sparse or slowly decaying
random potentials. In particular, we establish absence of absolutely continuous
surface spectrum for random potentials supported near a one-dimensional surface
(``random tube'') in arbitrary dimension.Comment: 14 pages, 2 figure
Die Bestimmung des Physiologischen Aminosäurenstatus von Möhren und Weizen zur Unterscheidung ökol. und konv. Anbauvarianten
A procedure for the differentiation and identification of organic versus conventional grown crop is described. The validated (ISO 17025) procedure is based on the precise Determination of the N-Metabolom of the cultivated plant. With this procedure it was possible to distinguish organically from conventionally grown crops
Identifizierung von ökol. u. konv. Anbauvarianten bei DOK-Weizen mittels Fluoreszenz-Anregungs-Spektroskopie
At coded samples of wheat out of the DOK-trial of FiBL (Switzerland) it was possible to identify the organic and conventional grown variants. The method used was fluorescence-excitation-spectroscopy of whole samples. It was also possible to show differences between biodynamic and organic variants
A quantitative central limit theorem for linear statistics of random matrix eigenvalues
It is known that the fluctuations of suitable linear statistics of Haar
distributed elements of the compact classical groups satisfy a central limit
theorem. We show that if the corresponding test functions are sufficiently
smooth, a rate of convergence of order almost can be obtained using a
quantitative multivariate CLT for traces of powers that was recently proven
using Stein's method of exchangeable pairs.Comment: Title modified; main result stated under slightly weaker conditions;
accepted for publication in the Journal of Theoretical Probabilit
Microbial transformation of elements: the case of arsenic and selenium
Microbial activity is responsible for the transformation of at least one third of the elements in the periodic table. These transformations are the result of assimilatory, dissimilatory, or detoxification processes and form the cornerstones of many biogeochemical cycles. Arsenic and selenium are two elements whose roles in microbial ecology have only recently been recognized. Known as “essential toxins”, they are required in trace amounts for growth and metabolism but are toxic at elevated concentrations. Arsenic is used as an osmolite in some marine organisms while selenium is required as selenocysteine (i.e. the twenty-first amino acid) or as a ligand to metal in some enzymes (e.g. FeNiSe hydrogenase). Arsenic resistance involves a small-molecularweight arsenate reductase (ArsC). The use of arsenic and selenium oxyanions for energy is widespread in prokaryotes with representative organisms from the Crenarchaeota, thermophilic bacteria, low and high G+C gram-positive bacteria, and Proteobacteria. Recent studies have shown that both elements are actively cycled and play a significant role in carbon mineralization in certain environments. The occurrence of multiple mechanisms involving different enzymes for arsenic and selenium transformation indicates several different evolutionary pathways (e.g. convergence and lateral gene transfer) and underscores the environmental significance and selective impact in microbial evolution of these two elements
Reciprocal Inhibition of Adiponectin and Innate Lung Immune Responses to Chitin and Aspergillus fumigatus
Chitin is a structural biopolymer found in numerous organisms, including pathogenic fungi, and recognized as an immune-stimulating pathogen associated molecular pattern by pattern recognition molecules of the host immune system. However, programming and regulation of lung innate immunity to chitin inhalation in the context of inhalation of fungal pathogens such as Aspergillus fumigatus is complex and our understanding incomplete. Here we report that the systemic metabolism-regulating cytokine adiponectin is decreased in the lungs and serum of mice after chitin inhalation, with a concomitant decrease in surface expression of the adiponectin receptor AdipoR1 on lung leukocytes. Constitutive lung expression of acidic mammalian chitinase resulted in decreased inflammatory cytokine gene expression and neutrophil recruitment, but did not significantly affect lung adiponectin transcription. Exogenous recombinant adiponectin specifically dampened airway chitin-mediated eosinophil recruitment, while adiponectin deficiency resulted in increased airway eosinophils. The presence of adiponectin also resulted in decreased CCL11-mediated migration of bone marrow-derived eosinophils. In contrast to purified chitin, aspiration of viable conidia from the high chitin-expressing A. fumigatus isolate Af5517 resulted in increased neutrophil recruitment and inflammatory cytokine gene expression in adiponectin-deficient mice, while no significant changes were observed in response to the isolate Af293. Our results identify a novel role for the adiponectin pathway in inhibition of lung inflammatory responses to chitin and A. fumigatus inhalation
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